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				<td><h1>CodeIgniter User Guide Version 2.1.3</h1></td>
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		<h1>Caching Driver</h1>

		<p>CodeIgniter features wrappers around some of the most popular
			forms of fast and dynamic caching. All but file-based caching require
			specific server requirements, and a Fatal Exception will be thrown if
			server requirements are not met.</p>

		<h2>Table of Contents</h2>
		<ul>
			<li><a href="#example_usage" title="Example Usage">Example
					Usage</a></li>
			<li><a href="#function_reference" title="Function Reference">Function
					Reference</a></li>
		</ul>

		<h3>Available Drivers</h3>
		<ul>
			<li><a href="#apc" title="APC Cache">Alternative PHP Cache
					(APC) Caching</a></li>
			<li><a href="#file" title="File Caching">File-based Caching</a></li>
			<li><a href="#memcached" title="Memcached">Memcached Caching</a></li>
			<li><a href="#dummy" title="Dummy Caching">Dummy Cache</a></li>
		</ul>

		<h2 id="example_usage">Example Usage</h2>

		<p>
			The following example will load the cache driver, specify <a
				href="#apc" title="APC">APC</a> as the driver to use, and fall back
			to file-based caching if APC is not available in the hosting
			environment.
		</p>

		<code>
			$this->load->driver('cache', array('adapter' => 'apc', 'backup' =>
			'file'));<br /> <br /> if ( ! $foo = $this->cache->get('foo'))<br />
			{<br /> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo 'Saving to the
			cache!&lt;br />';<br /> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$foo =
			'foobarbaz!';<br /> <br /> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// Save
			into the cache for 5 minutes<br />
			&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;$this->cache->save('foo', $foo, 300);<br />
			}<br /> <br /> echo $foo;
		</code>

		<h1 id="function_reference">Function Reference</h1>

		<h2>
			is_supported(
			<var>driver</var>
			['string'])
		</h2>

		<p>
			This function is automatically called when accessing drivers via
			<samp>$this->cache->get()</samp>
			. However, if the individual drivers are used, make sure to call this
			function to ensure the driver is supported in the hosting
			environment.
		</p>

		<code>
			if ($this->cache->apc->is_supported())<br /> {<br />
			&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;if ($data =
			$this->cache->apc->get('my_cache'))<br />
			&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;{<br />
			&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// do
			things.<br /> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}<br /> }
		</code>

		<h2>
			get(
			<var>id</var>
			['string'])
		</h2>

		<p>
			This function will attempt to fetch an item from the cache store. If
			the item does not exist, the function will return
			<samp>FALSE</samp>
			.
		</p>
		<code>$foo = $this->cache->get('my_cached_item');</code>

		<h2>
			save(
			<var>id</var>
			['string'],
			<var>data</var>
			['mixed'],
			<var>ttl</var>
			['int'])
		</h2>

		<p>
			This function will save an item to the cache store. If saving fails,
			the function will return
			<samp>FALSE</samp>
			.
		</p>
		<p>The optional third parameter (Time To Live) defaults to 60
			seconds.</p>
		<code>$this->cache->save('cache_item_id', 'data_to_cache');</code>

		<h2>
			delete(
			<var>id</var>
			['string'])
		</h2>

		<p>
			This function will delete a specific item from the cache store. If
			item deletion fails, the function will return
			<samp>FALSE</samp>
			.
		</p>
		<code>$this->cache->delete('cache_item_id');</code>

		<h2>clean()</h2>

		<p>
			This function will 'clean' the entire cache. If the deletion of the
			cache files fails, the function will return
			<samp>FALSE</samp>
			.
		</p>

		<code>$this->cache->clean();</code>

		<h2>cache_info()</h2>

		<p>This function will return information on the entire cache.</p>

		<code>var_dump($this->cache->cache_info());</code>

		<h2>
			get_metadata(
			<var>id</var>
			['string'])
		</h2>

		<p>This function will return detailed information on a specific
			item in the cache.</p>

		<code>var_dump($this->cache->get_metadata('my_cached_item'));</code>

		<h1>Drivers</h1>

		<h2 id="apc">Alternative PHP Cache (APC) Caching</h2>

		<p>All of the functions listed above can be accessed without
			passing a specific adapter to the driver loader as follows:</p>
		<code>
			$this->load->driver('cache');<br /> $this->cache->apc->save('foo',
			'bar', 10);
		</code>
		<p>
			For more information on APC, please see <a href="http://php.net/apc">http://php.net/apc</a>
		</p>

		<h2 id="file">File-based Caching</h2>

		<p>Unlike caching from the Output Class, the driver file-based
			caching allows for pieces of view files to be cached. Use this with
			care, and make sure to benchmark your application, as a point can
			come where disk I/O will negate positive gains by caching.</p>

		<p>All of the functions listed above can be accessed without
			passing a specific adapter to the driver loader as follows:</p>
		<code>
			$this->load->driver('cache');<br /> $this->cache->file->save('foo',
			'bar', 10);
		</code>

		<h2 id="memcached">Memcached Caching</h2>

		<p>
			Multiple Memcached servers can be specified in the memcached.php
			configuration file, located in the
			<samp>application/config/</samp>
			directory.
		<p>All of the functions listed above can be accessed without
			passing a specific adapter to the driver loader as follows:</p>
		<code>
			$this->load->driver('cache');<br />
			$this->cache->memcached->save('foo', 'bar', 10);
		</code>

		<p>
			For more information on Memcached, please see <a
				href="http://php.net/memcached">http://php.net/memcached</a>
		</p>

		<h2 id="dummy">Dummy Cache</h2>

		<p>This is a caching backend that will always 'miss.' It stores no
			data, but lets you keep your caching code in place in environments
			that don't support your chosen cache.</p>

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